Telephone-exchange system



Dec. 29 1925 1,567,242 E. H. CLARK TELEPHONE EXCHANGE SYSTEM Filed Oct. 26, 1923 5 Sheets-Sheet 1 Dec. 29. 1925- 1,567,242

E. H. CLARK TELEPHONE EXCHANGE SYSTEM Filed 001;. 26, 1923 5 Sheets-Sheet 2 Dec. 29, 1925- 1,567,242

E. H. CLARK TELEPHONE EXCHANGE SYSTEM Filed Oct. 2 1925 5 Sheets-Sheet 5 E M. CFJRRK TELEPHONE] EXCHANGE SYSTEM at. 26, 1925 5 Sheets-Sheet 4 dim a 4 M m mu wiw L J. /o 0 W I H 7 J .l 4 FM 4% W M M WE TI W M: M w 4 4 M W L .AHui M m L .4 k Ti v m HI; .I all. id: fl/WUWMuTT H dllllllvmwvmwflrm vwfi aw M b h flaming A 3.. l= w fl q a "H 2 a W, 2 Z j 7 4 5; v v w a a [Ml 3 4 Dec. 29, 1925- 1,567,242

E. H. CLARK TELEPHONE EXCHANGE SYSTEM Fi].ed (let. 26, 1923 5 Sheets-Sheet 5 J? M W Patented Dec. 29, 1925.

UNITED STATEE PATENT OFFICE.

EDGAR H. CLARK, OF RICHMOND HILL, NEW YORK, ASSIGNOE T0 WESTERN ELECTRIC COMPANY, INCORPORATED.

OF NEW YORK N. Y., A CORPORATION OF NEW YORK.

' TELEPHONE-EXCHANGE SYSTEM.

Application filed October 26, 1923. Serial No. 670,818.

To all whom it 'm-ag concern:

Be it known that I, EDGAR H. CLARK, a citizen of the United Statesof America, residing at Richmond Hill, in the county of Queens and State of New York, have invented certain new and useful Improvements in lelephoneExchange Systems, of which the l'ollowing is a full, clear, concise, and exact description. it

This invention relates to telephone exchange systems and especially to systems of the character in which automatic switching apparatus is employed for establishing connections.

The object of this invention is to improve and simplify telephone systems of the type using coordinate selective switches by transjmitting the switch operating impulses di- .1 ectly to said switches.

A feature of the invention relates to the provision of means whereby the impulses for setting the switches may be sent over the extended connection directly to the successive switches to selectively operate the same. 1

The several sheets of drawing have been arranged in the order illustrated in Fig. 6 and disclose a telephone exchange system employing switches of the coordinate type.

Fig. 1 shows diagrammatically a coordinate line switch in which the subscribers lines terminate.

Fig. 2 illustrates two separate first selector switches of the coordinate type in which appear trunks incoming from the line switches.

Fig. 3 shows certain controlling equipment associated with the first selector switches and the trunks outgoing therefrom. 3 Fig. l shows one of the number of trunks outgoing from the selector switch in Fig. 2 together with certain controlling equipment.

Fig. 5 shows a coordinate connector switch for completing connections to subscribers lines.

In the system shown, subscribers lines, such as the lines 101 and 102 incoming to the central ot'tlce, terminate in the line switches 100. @utgoing from these line switches are a number of trunks such as the trunks 103 and 104 which lead to first group selector switches. Trunks 103 and 104: are shown as appearing in the vertical rows 201 and 202 respectively of the coordinate group selector switch 200. Other trunks incoming from the same and other switches may terminate in the same group selector 200 or in other group selectors such as the selector 2] 0. Two additional trunks 226 and 227 are shown terminating in the group selector switch 210. i

Outgoing from the first group selector switches are a number of numerical groups cl trunks. Each of these groups of trunks is multipled so as to appear in a plurality of thefirstgroup selector switches 200, 210, etc, in order that access may be had through any of the several switches. The trunks are arranged on a numerical basis whereby each iuimerical group appears in a certain vertical row of contacts and in a certain portion of the row in each of the several switches to which they are multipled. Considering, the selector switch 200, for instance, the total number of horizontal links 207 208, 209, etc., are divided into two groups 205 and 206. .Vhile the section 205 is shown as containing only two links 207 and 208 and the section 206 is represented by a single link 209, it will be understood that each section may contain a large number of these horizontal links. Each vertical row 203 and 204, etc, is divided into two groups of trunks, namely, the group relating to the lower section of links 205 and the group relating to the upper section of links 206. All even numbered groups of trunks appear in the lower section of the vertical rows while all odd numbered groups of trunks appear in the upper section of the vertical rows. For instance, the group of trunks 22, 224, etc, appearing in the lower section of the vertical row 203 is numerically identified by the digit 2, while the group of trunks in the upper half of the vertical row 203 is identified by the digit 1, which is odd. Similarly, the group of trunks 221, 222, etc, is identified by the digit 4 while the group of trunks 223. etc, 111 the upper row of the vertical row 204 is identified by the digit 3. A similar grouping and allotment of the trunks occur in each of the other selector switches 210. It will be noted, for instance, that the trunk 5324. which occurs in the row 203 accessible to the link 207 in the switch 200 is multipled and occurs similarly in the switch 210 bei'ore the horizontal link 211. The same holds true with respect to all other trunks. Each of the vertical rows of contacts 203, 204-, etc., in the selector switch 200 is pro vided with an individual multi-contact relay .units digits.

- plurality 300, 301,302, 303, etc. Thepurpose of these relays Wlll be described hereinafter.

The trunks outgoing from the first selec- =tor .switches in the present disclosure are shownterminating in the vertical rows of contacts of connector switches such as the switch 500. The trunk 221 shown in full terminates in the vertical row of contacts 501 of the switch 500. A second trunk 523 is shown terminating in the vertical row of contacts 502.

The subscribers lines also terminate in the connector switches of the vertical rows 503, 504, etc. The horizontal links of theswitch 500are divided into ten groups, 506, 507, 508, etc, each of which represents one of the tens digits. Furthermore, each of the vertical rows 503, 504, etc., represents'one of the Accordingly, the line 515 appearing before the group of links 506 has No. 1 for its tens digit and since it occurs in the vertical row 503, also has No. 1 for its units digit. The line 516 has the same tens digit No. 1, but since it occurs in the vertical row504 has the No. 2 for its units digit. Similarly, the line 517 is identified by the tens digit 1 and the units digit 3. Each ofthe trunks leading from the line switch 100 to the first group selectors is provided with an individual stepping switch which serves to take the series of impulses directly from the dial and to determine the setting of the coordinate group selector switch accordingly. In Fig. 1, the stepping switch 105 is related to the trunk 104, while the second stepping switch 109 may, for instance, be associated with the other trunk 103.

Referring to the trunk'221 which leads from the first group selector to the connector switch 500, the stepping switches 400 and 401 shown in Fig. 4, are individual to this trunk and serve to receive the tens and units series of impulses for setting the connector switch 500. Each of the several trunks appearing in the connector switches is provided with a similar equipment.

By means of these individual recording switches associated with each of the trunks incoming to a selector switch, the switches may be set by means of the impulses transmitted directly thereto without the necessity of any common recording and controlling equipment located in the exchange. The coordinate switches employed in this system comprise briefly, a plurality of vertical operating bars, one for each vertical row of contacts for preparing said contacts for operation. In addition, there is provided a of horizontal operating bars, each individual-to one of the horizontal links for operating the contacts to establish connections between the incoming and outgoing lines by wayoi' the horizontal links. These operat ing bars are actuated by means of vertical and horizontal operating magnets. For a more detailed explanation'of the construction .N. Reynolds No. 1,515,735,..granted November 18, 1924, and the patent to S. B. Williams, No. 1,517,331, granted December 2, 1924.

The details of the connection will now he considered. line 101 initiates a call his line is extended through the line switch 100 to an idle trunk such asthe trunk 104. Immediately that the connection is extended through the calling line. Relay 116 operates a slow release relay 1 17 itclay 117 at its left contact applies ground potential to the test and holdingconductor 124 of the trunk 104.

Assuming that the number of the wanted line 517 is 413 the calling-subscriber first transmits aseries of four impulses. On the first opening of the line, relay 116 releases and closes an obvious circuit for operating slow release relay 118 and the stepping magnet 119. The magnet 119operates and steps the brushes 107 and 108 of the register switch 105 one step forward. For each successive opening and closure of the line, the brushes 107 and 108 are advanced until they reach their 4th position contacts. After an interval has elapsed following the series of impulses, the slow relay 118 becomes deenergized and operates the relay 106 which is individual to the trunk 104. A circuit for this purpose leads from battery, through the left winding of said relay, contact of relay 118, spring contacts 121 and 120 which are close'don-thejfirst step of the switch-105, common conductor 125, outer back contact of relay 114, to ground at the'contact ofslow operating relay 113. Relay 106 operates and prepares a locking circuit for itself and an operating circuit for relay 114. This circuit leads from battery, through the right winding and contact of relay 106, inner right back contact of relay 110, winding of relay 114 to ground at the contact of relay 113. Relay 106.closes an obvious circuit for the cut-off 115. Relay 115 releases the line relay l 116 which in turn opens the holding circuit of slow release relay 117. Before relay 117 can release to remove ground from the test conductor 124, another ground will be substituted in its place in the manner to be described hereinafter. Relay 114 operates the vertical magnet 214 in a circuit from ground, through the contactof relay 113, outer front contactof relay 114, conductor 126, inner left contact of relay 106, windt: 214 operates the bar associated with the vertical row of contacts in which appears the trunk 104, thuspreparing thesecontacts for operation. Relay 114 also operates the ing of the ma net 214 to battery.

-When the calling subscriber of the line. switch, line relay 116 operates in series with vertical operating magnet 216 and the multicontact relay 301 in a circuit from ground, through the contact of relay 113, inner contact of relay 114, outermost right armature of relay 106, brush 108 and its 4th position contact, conductor 127 and thence in parallel through the windings of the magnet 216 and the relay 301 to battery. Magnet 216 operates the bar associated with the vertical row of contacts 204 in the lower section of which appear the trunks of the group identified by the digit 4.

With the vertical'magnets 214 and 216 operated jointly, an energizing circuit is completed for the common control relay 113. This circuit leads from ground, through the contact of magnet 216, contact of relay 214 and thence through the winding of relay 113 to battery. Due to the fact that the relay 113 is slow in operating it does not open its contacts until after sufiicient time has expired for the operation of the selector switch 200 in the manner about to be discussed.

It will be assumed that the first trunk 221 in the chosen group is idle at this time. C0nsequently, when the test is made as will now be explained, the relay 306, which is individual to this trunk, will be found in a released condition. The testing circuit for associating the first idle trunk in the selected group may be traced from ground, through the contact of relay 113, inner contact of relay 114, middle right contact of relay 106, the brush 107 and its 4th position contact, conductor 228, spring contacts of the relay 301, conductor 310, innermost right back contact of relay 306, conductor 311, back contact of relay 219, left hand winding of the horizontal magnet 217 to battery. It will be noted that the circuit for the horizontal magnet 217 is closed at substantially the same time as the circuits for magnets 214 and 216. Magnet 217, however, being somewhat sluggish in operation does not ac tuate the bar 232 until after magnets 214 and216 have operated. The magnet 217 which is individual to the link 207, before which appears the idle trunk 221, operates in the above traced circuit and rotates the associated bar 232 to effect connection between the incoming trunk 104 and the outgoing trunk 221. The instant the connection is effected the circuit is completed from battery through both windings of the horizontal magnet 217, winding of relay 219 and thence through the contacts of switch 200 to the grounded test conductor 124 of the trunk 104. The relay 219, however, does not oper ate in this circuit since it is already shunted by the circuit above traced. Moreover, when the switch is operated a circuit is completed for the trunk relay 306 which is traceable from battery, through the resistance 307, winding of said relay, conductor 312, contacts of the switch 200 to the grounded test conductor 124. Relay 306, however, does not operate since it is shunted by-the circuit from battery, through the resistance 307, left back contact of relay 306 directly to the grounded conductor 310.

The foregoing operations, including the selection and operation of the idle horizontal magnet 217, take place before the slow relay 113 has time to operate. As soon as said relay finally does operate, it removes ground from the holding circuits or relay 106, vertical magnets 214 and 216 and also the multi contact relay 301. These relays and magnets thereupon release.

ll'ith the vertical operating magnets 214 and 216 released the connection established through the switch 200 is maintained by the continued energization of the horizontal operating magnet 217. p This connection extends by way of the trunk 221 whereupon the line relay 415, shown in Fig. 4, is connected directly in series with the calling subscribers line. Belay 415 operates the slow release 416 which applies ground potential to the holding conductor 312 of the' trunk Thus, ground is extended back over the test conductor to the conductor 124 of trunk 104 and the relay 115 is locked thereto through its inner left front contact. This locking circuit for relay 115 is completed before the relay 106 releases as above explained.

When relay 113 operates and 106 releases the shunt circuits around the windings of magnet 217, and relays 219 and 306 are re moved and these relays operate in the circuits already traced for them. The magnet 217 and relay 219 are now held in a circuit from battery. through the windings of magnet 217, winding of relay 219, contacts of the switch 200 and test conductor 312 to ground at the left contact of relay 416.

Relay 306, in operating, identifies the trunk 221 as busy in order to prevent any other switch from attempting to select this trunk.

Since the register switch 105 is no longer needed, it is immediately restored to normal. The circuit for this purpose may be traced from battery, through the winding and interrupting contact of the magnet 119, spring contacts 122 and 123, outer left contact of relay 115 to ground at the outermost left contact of relay 106. The magnet 119 steps the switch back to its normal position where the off-normal contacts 120, 121, 122 and 123 are opened and the switch comes to rest.

Next, the calling subscriber transmits a single impulse representing the tens digit. Upon the opening of the line circuit the relay 415 releases and closes an obvious circuit for slow to release relay 418 and the stepping magnet 402 of the tens register switch 400. At the end of the line interruption, the magnet 402 releases and the brush 403 is advanced :to ltS'filSt position the windings :of said .rel-ays, contacts of relay 420 and conductor v423 :to. groundat the contact ofrelay 412. Relay 419, however, being shunted,.does notv operate at this time. After an interval, relay .418 releases and removing the shunt permits relay 419 to operate.

Next, the subscriber transmits the units series of impulses consisting-{of three pulses. For-each interruption of the line, relay 415 releases and-a circuit is closed for the ,operation of the stepping vmagnet 404 of the register switch 1401. This circuit leads from ground, through the hack contact of relay 41:5, innerright contact ofqrelay .416, right contactof relay 417, winding of relay 418, right frontcontact of relay 419, winding .ofinagnet 404 to battery. After the switch 401 has, beensteppedto its3rd positioncontact, prelay 418 releases and causes the operation of relay 414. "The circuit for this purpose may be traced from battery,

:through -theleft winding of relay 414, back contact of relay 418, outer left contact of relay 419, off-normal spring contacts 408 and 409 of the switch 401, outer left contact of relay 413 to ground at the contact of relay 412. Relay 414 operates and locks throughits right winding and contact 111 a circuit which (also causes the operation of relay 413. 'LRelay 414, in operating, closes @5111 obvious circuit for the relay 417 which operates and locks to'the grounded conductor 312 of the trunk 221.

Relay 413 causestheoperation of the verticaloperating magnetfill in a circuit from ground, through the contact of relay 412,

inner contact of relay 413, inner left contact of'relay-414, and winding of magnet 511to battery. Magnet'51-1 operates the associated bar and prepares the contacts in the row 501 in which appears the trunk 221. Since theunits register switch 401 isstanding in its 3rd position, the relay 413, in op erating, causes the operation of the vertical .1nagnet514 which controls the row of contacts 505, in which appear lines having the units designation 3. The circuit for this purpose leads from ground, through the outer front contact of relay 413, outer right contact of relay 414, brush405 in position 3, winding of the magnet 514 to battery.

The joint operation of the magnets 51-1 and 514 closes a circuit for the slow operatingaelay 412 which isobvious from inspection. Relay 412 requires an interval to opcrate- ;during which time the connection is established through,the-switch500 as will he described presently. flhe joint operation of the mag-nets g5-11 -and 15,14 also results in the extension ofthe starterwvireto the group of horizontal :links 5506 whichhave access to the desired subscribers line 5 17. This :circuit may he traced from ground, through the contacts of magnets 514;an d511 thence oyer conductor 425,}brush .403 and its first position contact, conductor 1426, front contact of relay 520 (assuming-the link 509 to be busy), back contact of relay v521 (assuming .tlie linlz 5.10 to be idle) leftha-nd winding .of the horizontal operating magnet 519 battery. Magnet 5 19 operates the associated .bar ,525 and effects aconnection through the switch 500 whereby the trunk .221 is connected over link 510 to the subscribers line 5117. lmmediately when the connection is established a circuit is completed from hat- ,tery through the windings of magnet 5.19, winding ,of relay 521, through contacts ,of

the switch .500 to the test conductor 524 of the trunlr-221 to ground at the outer right contactof the relay 41 6. Relay .521, however, does not operate at this time.

After an interval, relay 412 attracts its armature and causes the ,release of relays 413,414, 419 and 420. NVith these relays released, the shunt is removed from around relay 521 and this relay operates in series mag e 1 Since the register switches 400 and 401 are no longer required for this connection they are restored to their normal positions. The circuit for restoring switch 400 may .betraced from battery, through the winding and contact of magnet .402, off-normal contacts406 and 407,.concluctor 427, outer left contactof relay 41? to ground at the left back'centact of relay 414. The circuit for restoring switch .401 extends from battery, through the-winding and contact of magnet 404 and 0if nor1nal contacts 410 and 411 to the grounded conductor 427. When the switches have reached their normal positions, their off-normal contacts are opened and the switches come to rest.

In any manner wellknown in the art, current may be-appliedto the called subscribers line 517 to inform him that a calling party is waiting. hen thecalled subscriber removes his receiver from the switchhook, talkingcurrent is supplied .to this line through the windings of relay .421.

After conversation has been completed, the subscribers replace their receivers on the switchhooks. When the calling subscriber hangs up his receiver,the. relay 415 releases and thereby -releases the relay 416. Relay 416, in turn, releases the relay 117. The release of these relays removes ground potential from the conductor 312 wherebythe connection through the switch 200 is disestablished. The called subscriber in replacing his receiver opens the circuit of relay 421 which removes ground potential from the conductor causing the release of the horizontal magnet 519 and the consequent disestablishment of the connection through the connector switch 500.

In case the first digit of the wanted number is odd, the selection takes place through the upper section 206 of the switch 200. If the digit is for instance, the group of trunks occurs in the upper part of the row 204, one of these trunks 223 being illustrated. The digit being three, the register switch 105 stands on its 3rd. position contact and the testing circuit for the horizontal magnets may be traced as follows: ground, through contact of relay 113, inner contact of relay 114:, middle right contact of relay 106, brush 107 in position 3, conductor 229. contacts of the relay 301, inner right back contact of trunk relay 313 (assuming the trunk 223 and the associated link 209 to be idle) right back contact of relay 230, left winding of horizontal magnet 231 to battery. In the manner fully described liereinbefore the horizontal magnet 231 effects connection through the switch 200 over the link 209 to the idle trunk 223.

Should the incoming call be extended over one of the trunks 226, 227 leading into the second selector switch 210, operations take place in the same manner as hereinbefore described and the connection is extended over an idle trunk to a connector switch.

The invention claimed is:

1. In a telephone system, a selective switch comprising a number of rows each including a plurality of separately operable sets of contacts, switching bars, one for each row, a line extending to said switch and appearing in the contacts thereof, and means individual to the line and responsive to impulses sent thereover directly to the switch for causing the operation of said bars to selectively extend the line through said switch.

2. In a telephone system, a selective switch comprising a number of rows each including a plurality of separately operable sets of contacts, switching bars, one for each row. a plurality of incoming lines appearing in the contacts of said switch, and means individual to each line and responsive to impulses sent thereover directly to the switch for causing the operation of said bars to selectively extend the line through said switch.

3. In a telephone system, a selective switch comprising a number of rows each including a plurality of separately operable sets of contacts, switching bars, one for each of said rows, other bars intersecting said first-mentioned bars and arranged for cooperation therewith, a telephone line extending to and appearing in contacts of said switch, and means associated with said line and responsive to impulses sent over the line directly to said switch for causing the operation of said bars to selectively extend the line through the switch.

4. In a telephone system, a selective switch comprising a number of rows each having a plurality of separately operable contact sets. links arranged in coordinate relation with said rows of contacts, switching bars. one for each row and one for each link, a line extending to said switch and appearing in the contacts thereof, and means associated with the line and responsive to impulses sent thereover directly to the switch for causing the cooperation of said bars to selectively extend the line through the switch.

5. In a telephone system, a selective switch having a number of rows each including a plurality of separately operable switch contacts. a plurality of links arranged in coordinate relation to said rows. incoming lines appearing in certain of said rows, numerical groups of outgoing lines appearing in other of said rows, switching bars, one for each row and one for each link, and means responsive to impulses sent directly over one of said incoming lines to the switch for causing the cooperation of said bars to extend the incoming line through one of said links to an outgoing line in a desired numerical group.

In witness whereof, I hereunto subscribe my name this 24th day of October, A. D. 1923.

EDGAR H. CLARK. 

